Signal readout structure for an image sensing apparatus

ABSTRACT

An image sensing apparatus includes a photoelectric converter having a plurality of pixels covered by a color filter composed of a plurality of colors, a plurality of common readout units adapted to sequentially output signals from the plurality of pixels, a time division multiplex (TDM) unit for time division multiplexing signals from the plurality of common readout units, and a readout control unit for reading the signals from the plurality of pixels to the common readout units in such a way that signals from pixels covered by color filters of the same color are continuously multiplexed.

This is a continuation of prior application Ser. No. 10/376,084, filedFeb. 28, 2003, now allowed. The prior application is incorporated hereinby reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to an image sensing apparatus, and moreparticularly, to a signal readout structure for an image sensingapparatus.

BACKGROUND OF THE INVENTION

Recent technical advances in digital still cameras, digital videocameras and other such image input devices have tended to providesensors with more and more picture elements (hereinafter pixels) inorder to further improve the quality of the images formed, with theresult that higher readout speeds are required as well. In order to meetsuch a need, a readout method has been developed by which the pixelsignals have been divided into a plurality of readout channels. Adescription of this conventional method is now given with reference toFIGS. 11 and 12.

FIG. 11 is a diagram of the structure of a conventional image sensingapparatus. FIG. 12 is a timing chart showing the drive timing and outputsignals of a conventional image sensing apparatus.

The image sensing apparatus shown in FIG. 11 has a plurality of pixels3101 arranged in two dimensions and consisting of optical black pixelsarranged and shielded by a light-blocking film and effective pixels withno light-blocking film; readout channels 3071 and 3072 for reading outimage signals from each of the plurality of pixels selected according toa control signal from a vertical scan circuit 3102; and an outputterminal 3120 for outputting signals after increasing either thewaveform or the drive force of the signals after the timing with whichthe signals are read out by the readout channels 3071, 3072 has beenadjusted and the signals have been passed through a buffer circuit 3119.Note that only 5×4 pixels are shown in FIG. 11 for simple explanation.

In addition, the readout channels 3071, 3072 have readout circuits 3106,3111, which in turn have line memories 3104, 3109 for storing pixelsignals read from each of the plurality of pixels 3101 and horizontalscan circuits 3105, 3110 for forwarding the stored pixel signals inresponse to horizontal shift pulses input from input terminals 3122,3123. In addition, the readout channels 3071, 3072 also have amplifiers3107, 3112 for amplifying the signals that are read out and clamps 3124,3125 for clamping the amplified signals at a particular electricpotential.

A description is now given of the operation of the conventional fixedimage sensing apparatus having the structure described above, withreference to FIG. 11.

First, when light strikes each of the plurality of pixels 3101, thepixels 3101 generate pixel signals of a level determined by the amountof incoming light. Next, pixel signals read out from odd-numberedcolumns in a row of pixels 3101 selected by the vertical scan circuit102 are stored in the line memory circuit 3104, and at the same timepixel signals read from even-numbered columns in the same row are storedin the line memory circuit 3109.

Next, the horizontal scan circuit 3105 inputs a horizontal shift pulsefrom either outside or inside the chip from the input terminal 3122.Based on the input horizontal shift pulse, the pixel signals read out tothe line memory circuit 3104 are then sequentially selected and outputto the amplifier 3107. At the amplifier 3107, the input pixel signalsare amplified and output to a processing circuit (not shown in thediagram) from an output terminal 3108.

Similarly, the horizontal scan circuit 3110, based on a horizontal shiftpulse input from the input terminal 3123, sequentially selects pixelsignals read out to the line memory circuit 3109 and outputs them to theamplifier 3112. At the amplifier 3112, the input pixel signals areamplified and output to a processing circuit (not shown in the diagram)from the output terminal 3113.

In addition, the dark level signals output from the optical black pixelswithin the plurality of-pixels 3101 are then clamped at a desiredelectric potential using clamps 3124, 3125. Further, at each of outputterminals 3108 and 3113, switches 3116 and 3117 connected in parallelare switched ON/OFF in alternating sequence so as to output pixelsignals from the odd-numbered columns of pixels and the even-numberedcolumns of pixels from the output terminal 3120 via the output buffercircuit 3119.

FIG. 12 shows horizontal shift pulses 1 and 2 input at input terminals3122, 3123 of FIG. 11, a dark level signal and a pixel signal outputfrom output terminals 3108 and 3113, a clamp pulse clamping, the ON/OFFaction of the switches 3116 and 3117, and a dark level signal and apixel signal output from output terminal 3120. FIG. 12 shows a state inwhich a pulse wave is input to input terminals 3122, 3123 in, forexample, 6 clock parts each.

In FIG. 12, of the signals output from output terminal 3120, the pixelsignals and dark level signals read out from pixels of a given row ofcolumns 1-12 are assigned reference numerals (1)-(12), respectively.Also, pixel signals of output terminals 3108 and 3113 are givenreference numerals corresponding to those of the signals at outputterminal 3120. Reference numerals (1)-(6) correspond to dark levelsignals obtained from the optical black pixels and reference numerals(7)-(12) correspond to the pixel signals from the effective pixels.

According to FIG. 12, the dark level signals (1), (3) and (5) and thepixel signals (7), (9) and (11), synchronized to horizontal shift pulse1, are sequentially output at the output terminal 3108. Similarly, darklevel signals (2), (4) and (6) and pixel signals (8), (10) and (12),synchronized to horizontal shift pulse 2, are sequentially output at theoutput terminal 3113. By activating the clamps 3124, 3125 at the pointat which the dark level signals (1) and (2) are output from the outputterminals 3108, 3113, the dark level signals are clamped at a desiredelectric potential.

Next, by switching switches 3116 and 3117 ON/OFF in alternatesuccession, the dark level signals (1)-(6) and the pixel signals(7)-(12) are output at the output terminal 3120. By so doing, althoughthe output terminals 3108 and 3113 operate at half-cycle with respect tothe clock rate at output terminal 3120, the readout speed can beincreased relatively easy.

Moreover, when reading out signals using multiple channels as describedabove, a structure that always reads out signals of the same color fromthe channels is disclosed in Japanese Patent Application Laid-Open No.9-46480, and a method for correcting offset error at each channel isdisclosed in Japanese Patent Application Laid-Open No. 2001-245221.

Moreover, Patent Application Japanese Laid-Open No. 5-328224 discloses astructure using multiple channels to read a plurality of pixels in thehorizontal direction and using a switch to perform time divisionmultiplexing on the signals read by the multiple channels. According tosuch a structure, even if the readout speed at each of the channels isslow, the charge readout can be read at high speed and the number ofterminals can be reduced by time division multiplexing of the read-outelectric charge signals.

However, Japanese Laid-Open Patent Application No. 9-46480 and2001-245221 have a disadvantage in that they increase the number ofoutput pins because four or five output pins are required for eachoutput terminal. In addition, Japanese Laid-Open Patent Application No.5-328224 has the following problem, described with reference to FIG. 13.

FIG. 13 is a diagram of the structure of another conventional imagesensing apparatus, illustrating the adaptation of the structuredisclosed in Japanese Laid-Open Patent Application No. 5-328224 to acolor readout. For the sake of simplicity, two horizontal scan circuitsare used to read out a charge from two pixels at a time. In FIG. 13, aplurality of pixels 1 are covered by a Bayer arrangement filter, withthe G-B pixel columns being read by the first horizontal scan circuit 3and the R-G pixel columns-being read by the second horizontal scancircuit 4.

In a case in which, as depicted here, an Nth line is selected and readout by the vertical scan circuit 2, a G signal of every other pixel iscontinuously output from a first differential amplifier 5 and an Rsignal of every other pixel is continuously read out from a seconddifferential amplifier 6. When time division multiplexed by amultiplexer 7, these G and R signals are output in alternating sequencefrom an output terminal (OUT).

However, by outputting signals of different colors from a single outputterminal using such multiplexing as described above, there is a riskthat the two colors will mix, and in any case such an arrangementcomplicates downstream signal processing circuit structures foroperations such as signal separation outside semiconductor image sensingapparatuses.

The reason is as follows: Parasitic resistance R and parasiticcapacitance C occurs in the wires inside the image sensing apparatus,and a change in electric potential in such wiring can be explained as atransient phenomenon. That is, the electric potential change in wiringwith such parasitic elements is determined by the parasitic resistance Rand the parasitic capacitance C, and with a time constant CR, a V(t) canbe expressed by equation (1):V(t)=V _(oε)−(1/RC)t  (1)where V_(o) is the electric potential in a steady state of the wiringand ε is a natural constant.

As can be understood from equation (1), V(t) changes exponentially withtime and approaches V_(o).

Thus, the waveform output from the output terminal 3120 of FIG. 11(output terminal 3120 of FIG. 12) has a different output level at (7)and (8), so it takes time for the electric potential to fall from (7) to(8), as is the case with the output level in the transition from (6) to(7). One of the reasons for the large differences in the continuousoutput level at the output terminal 3120 is that the outputs fromterminals 3113 and 3108 are outputs from pixels of color filters ofdifferent transmissivity.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made in consideration of theabove-described situation, and has as its object to output signals ofall colors at high speed from a color image sensing apparatus as well asform an image of superior picture quality which avoids color mixing evenwhen multiplexing signals from multiple output systems at high speedwith a comparatively simple structure, while holding the number ofoutput pins to a minimum.

According to the present invention, the foregoing objects are attainedby providing an image sensing apparatus comprising: a photoelectricconverter having a plurality of pixels covered by color filters composedof a plurality of colors; a plurality of common readout units adapted tosequentially output signals from the plurality of pixels, a timedivision multiplex (TDM) unit adapted to perform time divisionmultiplexing on signals from the plurality of common readout units so asto output time division multiplexed signals; and a read-out control unitadapted to read out the signals from the plurality of pixels to thecommon readout units so that signals from pixels covered with colorfilters of the same color are multiplexed continuously.

Other objects, features, effects and advantages of the present inventionwill be apparent from the following description, taken in conjunctionwith the accompanying drawings, in which like reference charactersdesignate the same or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention, in which:

FIG. 1 is a diagram of the structure of an image sensing apparatusaccording to a first embodiment of the present invention;

FIG. 2 is a timing chart showing the drive timing and output signals ofthe image sensing apparatus of FIG. 1;

FIG. 3 is a diagram of the structure of an image sensing apparatusaccording to a second embodiment of the present invention;

FIG. 4 is a timing chart showing the drive timing and output signals ofthe image sensing apparatus of FIG. 3;

FIG. 5 is a schematic diagram of the structure of an image sensingapparatus according to a third embodiment of the present invention;

FIG. 6 is a diagram of the structure of an image sensing apparatusaccording to a first variation of the present invention;

FIG. 7 is a diagram of the structure of an image sensing apparatusaccording to a second variation of the present invention;

FIG. 8 is a diagram of the structure of an image sensing apparatusaccording to a third variation of the present invention;

FIG. 9 is a diagram of the structure of an image sensing apparatusaccording to a fourth variation of the present invention;

FIG. 10 is a block diagram showing the structure of an image-formingsystem according to a fourth embodiment of the present invention;

FIG. 11 is a diagram of the structure of a conventional image sensingapparatus;

FIG. 12 is a timing chart showing the drive timing and output signals ofa conventional image sensing apparatus; and

FIG. 13 is a diagram of the structure of another conventional imagesensing apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described indetail in accordance with the accompanying drawings.

First Embodiment

A description is now given of the first embodiment of the presentinvention, with reference to FIGS. 1 and 2.

FIG. 1 is a diagram of the structure of an image sensing apparatusaccording to a first embodiment of the present invention. FIG. 2 is atiming chart showing the drive timing and output signals of the imagesensing apparatus of FIG. 1.

In FIG. 1, reference numeral 1 denotes a pixel having a Bayerarrangement color filter. The numbers inside the parentheses next to thecolor designations R (red), G (green) and B (blue), are the pixelcoordinates. It should be noted that, for simplicity of description, thepresent example uses a 6×6 arrangement of pixels, but in fact anextremely large number of pixels are arrayed in an actual arrangement.

The pixels 1 are each connected to line selection lines L1-L6 at eachline, with the line selection lines L1-L6 being turned HIGH (hereinafterH) in sequence by line selection signals supplied from the vertical scancircuit 2 and a line for reading the charge is selected. In the exampleshown in FIG. 2, a line selection signal ΦL1 supplied to the lineselection line L1 is H, selecting the first line (at a time t1). Atsubstantially the same time at which the readout line is selected andprior to the readout of the charge, signals ΦPTN1 and ΦPTN2 are turned Hand MOS 21, 22 are turned ON, reading the noise component of theselected line out to a capacitor CTN. Next, at a time t2, signals ΦPTS1and ΦPTS2 are turned H and MOS 23, 24 are turned ON, so that thephotoelectric charge accumulated in the pixels 1 of the selected line(which is a photoelectric charge overlaid with a noise component) isread out to the capacitor CTS. By so doing, the noise component and theimage signal component overlaid by the noise component of the pixels 1are each handled by the capacitors CTN and CTS, respectively.

Next, the charges held in capacitors CTN, CTS are sent to differentialamplifiers 15-18 by column selection signals supplied from first throughfourth horizontal scan circuits 11-14 comprised of shift resistors. Thedifferential amplifiers 15-18 subtract the noise components from theimage signal components overlaid by the noise components and outputimage signals from which the noise components are deleted.

At a time t3, the first and second horizontal scan circuits 11, 12 turnΦH1 and ΦH2 to H and the corresponding MOS 25-28 ON, so that the chargesread from G (1,1) and R (1,2) to the capacitors CTN, CTS are each sentto the differential amplifiers 15 and 16 via signal lines 101, 102.Differential amplifier 15 deletes the noise component from thephotoelectric charge overlaid with the noise component and outputs(OUT1) an image signal (denoted by the same reference numeral as thepixels, in this case G (1,1)). Similarly, differential amplifier 16outputs image signal R (1,2) (OUT2). Multiplexers 19 and 20 each selectdifferential amplifiers 15 and 16 and output image signals G(1,1) andR(1,2), respectively.

Then, at a time t4, the third and fourth horizontal scan circuits 13 and14 turn ΦH3 as well as ΦH4 to H, sending the charges read to thecapacitors CTN and CTS from G(1,3) and R(1,4) to the respectivedifferential amplifiers 17 and 18 via the signal lines 103, 104.

Then, the differential amplifier 17 removes the noise component from thephotoelectric charge overlaid with the noise component, outputting imagesignal G(1,3) (OUT3). Similarly, the differential amplifier 18 outputsimage signal R (1,4) (OUT4). The multiplexers 19 and 20 then outputimage signals G(1,3) and R(1,4), respectively, by selecting thedifferential amplifiers 17, 18.

By repeating the above-described process for each horizontal line, Gsignals G(1,1), G(1,3), G(1,5) of every other pixel are output fromoutput terminal OUT A of multiplexer 19 and R signals R(1,2), (1,4),(1,6) of every other pixel are output from output terminal OUT B ofmultiplexer 20.

Similarly, selecting a second line by having the vertical scan circuit 2turn ΦL2 to H and repeating the above-described operation for one linecauses B signals B(2,1), B(2,3), B(2,5) of every other pixel to beoutput from output terminal OUT A of multiplexer 19, and G signalsG(2,2), G(2,4) and G(2,6) of every other pixel to be output from outputterminal B of multiplexer 20.

As described above, according to the first embodiment of the presentinvention, by reading out and multiplexing signals output via multiplereadout signal lines, the speed of readout can be improved and at thesame time the number of output pins can be reduced compared to a case inwhich signals are output directly from the readout signal lines. Also,because the present invention multiplexes signals of the same color, thesignal level of the outputs from OUT A and B can be kept virtuallysteady, thus avoiding color mixing and making it possible to outputcolor signals from a color fixed image sensing apparatus at high speeds.Also, by allotting the color output system among multiple readout meansas shown in FIG. 1 like the first embodiment, it becomes possible tomultiplex the top two system readout means as well as the bottom twosystem readout means. Moreover, since the top OUT1 and OUT3 are adjacentto each other, and since the bottom OUT2 and OUT4 are also adjacent toeach other, the problem of delay and the drive force can be ignored sothat the timing of the multiplexing can be adjusted easily.

Moreover, since signals of the same color are output from the outputpins, there is no need to perform color separation at a downstreamsignal processing circuit, thus making it possible to simplify thestructure and the processes of such signal processing circuit.

Second Embodiment

A description will now be given of the second embodiment of the presentinvention, with reference to the accompanying drawings.

It should be noted that, in order to simplify the explanation, adescription of the drive method and noise deletion method is omitted forthe second and all subsequent embodiments of the present inventiondescribed herein below.

FIG. 3 is a diagram of the structure of an image sensing apparatusaccording to a second embodiment of the present invention. FIG. 4 is atiming chart showing the drive timing and output signals of the imagesensing apparatus of FIG. 3. As can be seen in FIG. 3, in the secondembodiment, the first and third horizontal scan circuits 11 and 13 ofthe first embodiment shown in FIG. 1, as well as the second and fourthhorizontal scan circuits 12 and 14 also shown in FIG. 1, have each beenreplaced with a single horizontal scan circuit. It should be noted that,in FIG. 3, structures that are the same as those shown in FIG. 1 aregiven identical reference numerals.

In FIG. 3, reference numeral 31 denotes a first horizontal scan circuitand reference numeral 32 denotes a second horizontal scan circuit. Asshown in FIG. 4, the cycle of the clock signal supplied to the first andsecond horizontal scan circuits 31, 32 is twice the drive frequency ofthe first through fourth horizontal scan circuits 11-14 of the firstembodiment.

Based on the cycle of the supplied clock, the first horizontal scancircuit 31 turns ΦH1, ΦH3 and ΦH5 high in succession and the secondhorizontal scan circuit 32 turns ΦH2, ΦH4 and ΦH6 high in succession, sothat readout can be performed at the same timing as that of the firstembodiment described above.

Third Embodiment

A description will now be given of a third embodiment of the presentinvention, with reference to the accompanying drawings.

FIG. 5 is a schematic diagram of the structure of an image sensingapparatus according to a third embodiment of the present invention. FIG.5 shows an arrangement in which the signal lines 101-104 depicted inFIG. 1 and FIG. 3 output to left and right lateral directions from acenter thereof. It should be noted that, in FIG. 5, structures that areidentical to those shown in FIGS. 1 and 3 are given identical referencenumerals, and structures equivalent to those shown in FIGS. 1 and 3 butdivided into lateral arrangements are given reference numerals followedby the reference symbol R (right) or L (left), as appropriate. Also, ascan be appreciated by those of ordinary skill in the art, the structureshown in FIG. 5 can be easily adapted to the image sensing apparatus ofthe first embodiment described above.

Fourth Embodiment

Next, a description is given of a still camera image forming systemusing the image sensing apparatus described in the first, second andthird embodiments described above, with reference to FIG. 10.

FIG. 10 is a block diagram showing the structure of an image-formingsystem according to a fourth embodiment of the present invention. InFIG. 10, reference numeral 401 denotes a barrier that functions as alens protector and as a main switch. Reference numeral 402 denotes alens that focuses an optical image of a subject at the image sensingapparatus 404. Reference numeral 403 denotes an aperture for controllingthe amount of light that passes through the lens 402. Reference numeral404 denotes an image sensing apparatus (corresponding to the imagesensing apparatus described above in the first, second and thirdembodiments) for handling the subject optical image formed by the lens402 as an image signal. Reference numeral 405 denotes an image signalprocessing circuit that includes a gain variable amplifier foramplifying image signals output from the image sensing apparatus 404 anda gain correction circuit for correcting the gain. Reference numeral 406denotes an A/D converter for converting the analog image signals outputby the image sensing apparatus 404 into digital signals. Referencenumeral 407 denotes a signal processor for applying a variety ofcorrections and compression to image data output from the A/D converter406. Reference numeral 408 denotes a timing generator for outputtingtiming signals to the image sensing apparatus 404, the image signalprocessing circuit 405, the A/D converter 406 and the signal processor407. Reference numeral 409 denotes a controller/calculator for exertingoverall controlling of various calculations and of the still videocamera as a whole. Reference numeral 410 denotes a memory fortemporarily storing image data. Reference numeral 411 denotes arecording medium control interface for recording on and reading from arecording medium. Reference numeral 412 denotes a semiconductor memoryor other detachable recording medium for recording and/or providingimage data. Reference numeral 413 denotes an external interface forcommunicating with an external computer or the like.

Next, a description is given of the operation of the still video camerahaving the structure described above during image sensing operation.

When the barrier 401 is opened, the main power switch is turned ON, thecontrol system power is turned ON, and further, the power to the imageforming system circuitry such as the A/D converter is turned ON.

Then, in order to control the amount of exposure light, thecontroller/calculator 409 opens the aperture 403 and signals output fromthe image sensing apparatus 404 are converted from analog signals intodigital signals by the A/D converter 406, after which the digitalsignals are input to the signal processor 407. The controller/calculator409 gauges the amount of light involved by using data that has undergonepredetermined processes by the signal processor 407, determines thebrightness and calculates the exposure. The aperture 403 is thenadjusted according to the exposure thus obtained.

Next, the controller/calculator 409 uses the signals output from theimage sensing apparatus 404 to extract a high-frequency component andcalculate the distance to the subject. The controller/calculator 409then drives the lens and determines if the subject is in focus and, ifthe subject is not in focus, drives the lens again and measures thedistance to the subject. Exposure commences once proper focus isachieved.

When exposure is completed, the image signals output from the imagesensing apparatus 404 are A/D converted by the A/D converter 406 andwritten to the memory 410 via the signal processor 407 under the controlof the controller/calculator 409.

Thereafter, the controller/calculator 409 writes the data accumulated inthe memory 410 to the removable recording medium 412 via the recordingmedium controller I/F 411.

Or, the controller/calculator 409 may input the data accumulated in thememory 410 directly to the computer for image processing via theexternal I/F 413.

Other Embodiments

A description is now given of other and further variations of theembodiments of the present invention, with reference to FIGS. 6, 7, 8and 9.

FIG. 6 is a diagram of the structure of an image sensing apparatusaccording to a first variation of the present invention. FIG. 7 is adiagram of the structure of an image sensing apparatus according to asecond variation of the present invention. FIG. 8 is a diagram of thestructure of an image sensing apparatus according to a third variationof the present invention. FIG. 9 is a diagram of the structure of animage sensing apparatus according to a fourth variation of the presentinvention.

In the first, second and third embodiments described above, Bayerarrangement color filters are used, the four signal readout systems (thedifferential amplifiers 15-18, and the signal wires 101-104 whichconnects between capacitors CTN, CTS and the differential amplifiers15-18) and two multiplexers 19 and 20 are used to obtain two outputs.However, as can be appreciated by those of ordinary skill in the art,the present invention is not limited to such arrangements, as isindicated by FIGS. 6-9. Thus, for example, the signal readout componentsmay be constituted so as to comprise six systems (as depicted in FIG. 6)or even eight systems (as in FIG. 7). In such cases, even if the readoutspeed at the signal readout components does not change compared to acase in which one system is used, the sensor signal output rate can beincreased three- and four-fold, respectively. In addition, by providinga horizontal scan circuit on each signal readout component, the clockfrequency used at the horizontal scan circuit can be reduced to ⅓ or ¼compared to a case in which a single horizontal scan circuit is used formultiple signal readout components.

In addition, the color arrangement of the color filter can be changed asneeded, provided that the number of signal readout systems is at leasttwice the maximum number of colors of the color filters covering thepixels included in the lines. For example, if the color filter has alayout that repeats the sequence R,G,B in every line, a signal readoutcomponents arrangement comprising at least six systems may be used (FIG.8)

In addition, the color filter need not be limited to the primary colors.Instead, a complementary color filter may be used (see FIG. 9).

The present invention is not limited to the above-described embodiments,and various changes and modifications can be made within the spirit andscope of the present invention. Therefore, in order to apprise thepublic of the scope of the present invention, the following claims aremade.

1. An image sensing apparatus having a plurality of first pixel lineseach including a plurality of pixels corresponding to a first color anda plurality of pixels corresponding to a second color, and a pluralityof second pixel lines each including a plurality of pixels correspondingto the second color and a plurality of pixels corresponding to a thirdcolor, said apparatus comprising: a plurality of first capacitors thatstore signals from the pixels corresponding to the first color andsignals from the pixels corresponding to the second color included inthe second pixel lines; a plurality of second capacitors that storesignals from the pixels corresponding to the second color included inthe first pixel lines and signals from the pixels corresponding to thethird color; a plurality of first signal lines through which the signalsof said plurality of first capacitors are read; a plurality of secondsignal lines through which the signals of said plurality of secondcapacitors are read; a plurality of first switches that controlconnection of said plurality of first capacitors and said plurality offirst signal lines; a plurality of second switches that controlconnection of said plurality of second capacitors and said plurality ofsecond signal lines; a first multiplexer that multiplexes the signalsfrom said plurality of first signal lines and outputs the signals fromsaid plurality of first signal lines as a first output; and a secondmultiplexer that multiplexes the signals from said plurality of secondsignal lines and outputs the signals from said plurality of secondsignal lines as a second output which is different from said firstoutput, wherein signals of pixels corresponding to one of said first,second and third colors are consecutively output from said plurality offirst and second signal lines as said first and second outputs.
 2. Theimage sensing apparatus according to claim 1, wherein said firstmultiplexer outputs consecutive signals of the first color or the secondcolor and said second multiplexer outputs consecutive signals of thesecond color or the third color, wherein, during a first predeterminedperiod, said first and second colors are output as said first and secondoutputs, respectively, at substantially the same time, and wherein,during a second predetermined period, said second and third colors areoutput as said first and second outputs, respectively, at substantiallythe same time.
 3. The image sensing apparatus according to claim 1,wherein said plurality of first capacitors, said plurality of firstsignal lines and said first multiplexer are arranged on one side of theplurality of first and second pixel lines, and said plurality of secondcapacitors, said plurality of second signal lines and said secondmultiplexer are arranged on the opposite side of the plurality of firstand second pixel lines.
 4. The image sensing apparatus according toclaim 1, wherein the first color is red, the second color is green, andthe third color is blue.
 5. An image sensing apparatus having aplurality of pixels arranged in rows and columns, comprising: a pixelarray arranged so that first and second pixels corresponding to a firstcolor, and third and fourth pixels corresponding to a second color arearranged in one line, wherein the first pixel connects to a firstcapacitor via a first switch, the first capacitor connecting to a firstcommon signal line via a second switch, wherein the second pixelconnects to a second capacitor via a third switch, the second capacitorconnecting to a second common signal line via a fourth switch, andwherein the first common signal line and the second common signal lineare connected to a multiplexer so that a signal of the first pixel and asignal of the second pixel are output alternately.
 6. The image sensingapparatus according to claim 5, wherein a plurality of first groups eachincluding the first pixel, the first switch, the first capacitor and thesecond switch are arranged, and the second switches of the plurality offirst groups are connected to the first common signal line, and whereina plurality of second groups each including the second pixel, the thirdswitch, the second capacitor and the fourth switch are arranged, and thefourth switches of the plurality of second groups are connected to thesecond common signal line.
 7. The image sensing apparatus according toclaim 5, wherein the third pixel connects to a third capacitor via afifth switch, the third capacitor connecting to a third common signalline via a sixth switch, wherein the fourth pixel connects to a fourthcapacitor via a seventh switch, the fourth capacitor connecting to afourth common signal line via eighth switch, wherein the third commonsignal line and the fourth common signal line are connected to amultiplexer, different from the multiplexer to which the first andsecond common signal lines are connected, so that a signal of the thirdpixel and a signal of the fourth pixel are output alternately.
 8. Theimage sensing apparatus according to claim 7, wherein the pixel arrayincludes another line in which fifth and sixth pixels corresponding tothe first color, and seventh and eighth pixels corresponding to a thirdcolor are arranged, wherein the fifth pixel connects to the thirdcapacitor, the sixth pixel connects to the fourth capacitor, the seventhpixelconnects to the first capacitor, and the eighth pixel connects tothe second capacitor, wherein the multiplexer to which the first andsecond common signal lines are connected alternately outputs a signal ofthe seventh pixel and a signal of the eighth pixel, and wherein themultiplexer to which the third and fourth common signal lines areconnected alternately outputs a signal of the fifth pixel and a signalof the sixth pixel.
 9. The image sensing apparatus according to claim 8,wherein the first color is green, the second color is red, and the thirdcolor is blue.